(a) Technical Field
The present disclosure relates generally to a device for a vehicle. More particularly, it relates to a device for operating a horn of a vehicle.
(b) Background Art
In many vehicles, an airbag module for the driver's seat is typically installed in a central portion of the steering wheel, and a horn cover is formed on a front surface of the central portion of the steering wheel. The horn cover not only serves as a cover for the airbag module, but is also used for operating the horn.
As shown in FIG. 1, a conventional airbag module 20 is disposed in a central portion of a steering wheel 10, and the entire surface of the airbag module 20 is covered by a cover 22 used for operating a horn. A plurality of compressible coil springs 30 are connected between a frame 12 of the steering wheel 10 and the bottom of the airbag module 20 covered by the cover 22. When the airbag module 20 explodes, the cover 22 is torn to deploy an airbag.
As shown in FIG. 2, which illustrates a circuit configuration for operating the horn, a contact switch 24 is mounted between the frame 12 of the steering wheel 10 and the bottom of the airbag module 20 covered by the cover 22. The contact switch 24 is connected to the horn 28 through a relay 26. Therefore, when a driver holds down the cover 22 in order to operate the horn, both of the cover 22 and the airbag module 20 are moved downward while compressing the coil springs 30. When the driver takes his or her hand off the cover 22, the horn cover 22 and the airbag module 20 are moved upward to the original position by the elastic restoring force of the coil spring 30.
At this time, when the driver holds down the cover 22 such that both of the cover 22 and the airbag module 20 are moved downward to a predetermined length or more while compressing the coil springs 30, a switching-on state is achieved while electricity is conducted through the contact switch 24. The horn 28 generates a horn sound as a result.
However, the conventional horn operating device demonstrated in FIGS. 1 and 2 has the following problems.
First, when the repulsive force of the coil spring is lowered for an operation of the horn, as illustrated in FIG. 3, a rattle may occur. Conversely, when the repulsive force of the coil spring is raised to prevent the rattle, a horn operating force needed to operate the horn may increase. The horn operating force refers to a force required for moving the airbag module downward while overcoming the repulsive force of the coil spring.
As an example, the horn operating force applied by the driver may be set to 3 Kgf or more when the driver holds down the cover. In this case, the driver may experience a heavy operating sensation while holding down the cover. On the other hand, when a coil spring with a low repulsive force is employed in order to reduce the horn operating force, the driver may operate the horn with a small force, but the support force of the coil spring on the airbag module may be weakened. In this case, the entire airbag module may rattle due to driving vibration.
Second, since a gap corresponding to the height of the coil spring is formed between the airbag module and the frame of the steering wheel, the horn operating force may be further increased when wiring is caught in the gap. In a worst case, the horn may not be operable while the downward movement of the airbag module is disturbed.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the disclosure, and therefore, it may contain information that does not form the related art that is already known in this country to a person of ordinary skill in the art.